topic Re: EF 50mm 1.8 STM Manual focus not working in EF & RF Lenses

EF 50mm 1.8 STM Manual focus not working

Dracosin — Thu, 26 Dec 2024 05:57:41 GMT

Merry Christmas! Happy Holidays!

My issue is the following:

The mentioned lens will not manual focus. I've tried the following:

Pressing shutter "halfway" with switch in MF (nope)
Pressing shutter "halfway" with switch in AF (I read this sometimes works, but still nope)
Applying pressure to the ring to turn it
Letting it focus in AF and then switching to MF.
Detaching and reattaching the lens

Autofocus works. The lens is amazing and shoots wonderfully! It's just the manual focus isn't doing what focus should do. My two kit lenses work well in auto and manual focus as well.

Camera: Canon EOS 4000D
Firmware 1.1.0 (updating is on my next list, if there's an update for it)

Any suggestions besides a firmware upgrade?

Edit: I was able to get it to manual focus but only if I squeezed the ring like I was opening a can of pickles. I believe my only option is to return it back to where I bought it and get a different one.

Re: EF 50mm 1.8 STM Manual focus not working

deebatman316 — Wed, 25 Dec 2024 19:22:26 GMT

Make sure the camera is set to One Shot AF. If it’s set to AI Focus or Servo AF the focus ring is DISABLED. The focus ring on STM lenses are electronic. There is no mechanical connection to the lens focusing system. The AF motor is used for MF. If the camera is in Auto Mode or any other Automated shooting mode it doesn’t work. Ensure USM Lens Electronic Manual Focus/ Lens Electronic Manual Focus is enabled.

Re: EF 50mm 1.8 STM Manual focus not working

Waddizzle — Wed, 25 Dec 2024 21:38:22 GMT

Demetrius makes a good point.

The focusing mechanism is not mechanically connected to the focus ring on the lens body. The only time the focusing mechanism can respond, either manually or automatically, is when the metering system is active and displaying exposure information.

Re: EF 50mm 1.8 STM Manual focus not working

Dracosin — Thu, 26 Dec 2024 05:03:40 GMT

The only thing I can't figure out is how to enable the electronic manual focus? I've checked settings and found some settings I didn't know existed to try and find this setting which doesn't exist.

The focus ring is not tight, feels as loose as my other manual focus rings, yet it still autofocuses just fine. Should the ring move when autofocus is activated?

Re: EF 50mm 1.8 STM Manual focus not working

deebatman316 — Thu, 26 Dec 2024 13:06:21 GMT

No the focus ring is electronic. It’s not mechanically connected to the lens element. It won’t move when AF is being performed. If the camera is set to Full Auto or any other automated shooting mode. The full camera menu IS NOT AVAILABLE. Lenses with cheaper slower AF motors such as Micro Motor & Micro Motor USM. Spin the focus ring when AF is being performed. But STM, Ring Type USM & Nano USM the focus ring doesn’t spin.

Re: EF 50mm 1.8 STM Manual focus not working

Dracosin — Tue, 31 Dec 2024 17:49:36 GMT

So I returned to lens to Target, where I had purchased it. They didn't have more so I ordered one from the giant internet Jungle.

The new one works like it should!

Some key points I should have been more cautious about:

The previous one, when I opened it, had the paper documentation crammed next to it, while the new one has this little cardboard shelf on top of it.

The previous one was wrapped in just bubble wrap, while the new one was wrapped in bubble wrap and another piece of plastic bag.

The previous one, when I went to turn the focus ring, was very loose and didn't feel attached to anything at all. The new one has a bit more tension and I feel the motor engage, even hearing the motor whirring up.

So it was indeed broke. And anyone who might have a question about this lens later hopefully will find this helpful.

Re: EF 50mm 1.8 STM Manual focus not working

deebatman316 — Tue, 31 Dec 2024 18:00:44 GMT

The focus ring on STM lenses is NOT connected to the lens' focusing system. The focus ring is only connected to a digital encoder that tells the camera that you're turning the focus ring. So it will turn indefinitely and have no tension on it.